Re: Index-only scans

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Index-only scans
Date: 2009-07-13 13:38:18
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Heikki Linnakangas wrote:
> Even if we don't solve the visibility
> map problem, just allowing the executor to evaluate quals that are not
> directly indexable using data from the index, would be useful. For
> example, "SELECT * FROM foo WHERE textcol LIKE '%bar%', and you have a
> b-tree index on textcol, the planner could choose a full-index-scan,
> apply the '%bar%' filter on the index tuples, and only fetch those heap
> tuples that match that qual.

Interesting, I had not considered that. You are using the index as a
single-column table that can be scanned more quickly than the heap.

Bruce Momjian <bruce(at)momjian(dot)us>

+ If your life is a hard drive, Christ can be your backup. +

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